From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Michael Walle <michael@walle.cc>
Cc: Marcelo Roberto Jimenez <marcelo.jimenez@gmail.com>,
Andrew Chant <achant@google.com>,
Edmond Chung <edmondchung@google.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Linus Walleij <linus.walleij@linaro.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
regressions@lists.linux.dev,
Stephen Rothwell <sfr@canb.auug.org.au>,
stable <stable@vger.kernel.org>,
Sergio Tanzilli <tanzilli@acmesystems.it>,
Thierry Reding <treding@nvidia.com>,
Vidya Sagar <vidyas@nvidia.com>,
Will McVicker <willmcvicker@google.com>,
Horatiu Vultur <horatiu.vultur@microchip.com>,
Lars Povlsen <lars.povlsen@microchip.com>
Subject: Re: [PATCH] gpio: Revert regression in sysfs-gpio (gpiolib.c)
Date: Tue, 15 Mar 2022 16:32:08 +0100 [thread overview]
Message-ID: <CAMRc=MfH00YJv07TaiZ5z1w4gzqP5_8z9bKFcNU1Z37AVih4hQ@mail.gmail.com> (raw)
In-Reply-To: <20220314155509.552218-1-michael@walle.cc>
On Mon, Mar 14, 2022 at 4:55 PM Michael Walle <michael@walle.cc> wrote:
>
> Hi,
>
> > Some GPIO lines have stopped working after the patch
> > commit 2ab73c6d8323f ("gpio: Support GPIO controllers without pin-ranges")
> >
> > And this has supposedly been fixed in the following patches
> > commit 89ad556b7f96a ("gpio: Avoid using pin ranges with !PINCTRL")
> > commit 6dbbf84603961 ("gpiolib: Don't free if pin ranges are not defined")
> >
> > But an erratic behavior where some GPIO lines work while others do not work
> > has been introduced.
> >
> > This patch reverts those changes so that the sysfs-gpio interface works
> > properly again.
> >
> > Signed-off-by: Marcelo Roberto Jimenez <marcelo.jimenez@gmail.com>
>
> This breaks the pinctrl-microchip-sgpio driver as far as I can see.
>
> I tried to debug it and this is what I have discovered so far:
> (1) the sgpio driver will use the gpio_stub_drv for its child nodes.
> Looks like a workaround, see [1].
> (2) these will have an empty gpio range
> (3) with the changes of this patch, pinctrl_gpio_request() will now
> be called and will fail with -EPROBE_DEFER.
>
> I'm not exactly sure what to do here. Saravana Kannan once suggested
> to use devm_of_platform_populate() to probe the child nodes [2]. But
> I haven't found any other driver doing that.
>
TI AEMIF driver (drivers/memory/ti-aemif.c) does something like this:
406 if (np) {
407 for_each_available_child_of_node(np, child_np) {
408 ret = of_platform_populate(child_np, NULL,
409 dev_lookup, dev);
410 if (ret < 0) {
411 of_node_put(child_np);
412 goto error;
413 }
414 }
415 } else if (pdata) {
416 for (i = 0; i < pdata->num_sub_devices; i++) {
417 pdata->sub_devices[i].dev.parent = dev;
418 ret =
platform_device_register(&pdata->sub_devices[i]);
419 if (ret) {
420 dev_warn(dev, "Error register sub
device %s\n",
421 pdata->sub_devices[i].name);
422 }
423 }
424 }
A bunch of different devices (like NAND) get instantiated this way.
Would this work?
Bart
> Also, I'm not sure if there are any other other driver which get
> broken by this. I.e. ones falling into the gpio_stub_drv category.
>
> [1] https://lore.kernel.org/lkml/20210122193600.1415639-1-saravanak@google.com/
> [2] https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com/
>
> -michael
>
> NB. this patch doesn't contain a Fixes tag. Was this on purpose?
next prev parent reply other threads:[~2022-03-15 15:32 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 15:35 [PATCH] gpio: Revert regression in sysfs-gpio (gpiolib.c) Marcelo Roberto Jimenez
2021-12-18 6:28 ` Thorsten Leemhuis
2021-12-20 14:57 ` Bartosz Golaszewski
2021-12-20 15:14 ` Geert Uytterhoeven
2021-12-20 19:24 ` Will McVicker
2021-12-20 20:41 ` Marcelo Roberto Jimenez
2021-12-20 20:41 ` Marcelo Roberto Jimenez
2021-12-20 20:41 ` Marcelo Roberto Jimenez
2022-01-10 7:02 ` Thorsten Leemhuis
2022-01-12 0:09 ` Marcelo Roberto Jimenez
2022-02-08 12:24 ` Thorsten Leemhuis
2022-02-17 19:11 ` Thierry Reding
2022-05-30 13:43 ` [PATCH] gpio: Revert regression in sysfs-gpio (gpiolib.c) #forregzbot Thorsten Leemhuis
2022-02-11 0:02 ` [PATCH] gpio: Revert regression in sysfs-gpio (gpiolib.c) Linus Walleij
2022-02-11 22:36 ` Marcelo Roberto Jimenez
2022-02-12 16:54 ` Linus Walleij
2022-02-13 23:23 ` Marcelo Roberto Jimenez
2022-02-15 21:56 ` Linus Walleij
2022-02-16 14:40 ` Bartosz Golaszewski
2022-03-04 7:13 ` Thorsten Leemhuis
2022-03-07 9:58 ` Bartosz Golaszewski
2022-03-07 10:12 ` Thorsten Leemhuis
2022-03-15 5:18 ` [PATCH] gpio: Revert regression in sysfs-gpio (gpiolib.c) #forregzbot Thorsten Leemhuis
2022-05-20 9:12 ` [PATCH] gpio: Revert regression in sysfs-gpio (gpiolib.c) Thorsten Leemhuis
2022-05-20 17:28 ` Marcelo Roberto Jimenez
2022-03-14 15:55 ` Michael Walle
2022-03-15 15:32 ` Bartosz Golaszewski [this message]
2022-03-15 15:45 ` Michael Walle
2022-03-17 8:37 ` Andy Shevchenko
2022-03-17 8:48 ` Michael Walle
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